# physics

posted by .

A charge of +q is located at the origin, while an identical charge is located on the x axis at x = 0.45 m. A third charge of +4q is located on the x axis at such a place that the net electrostatic force on the charge at the origin doubles, its direction remaining unchanged. Where should the third charge be located?

I am just supposed to be using Coulombs law. I tried in relation to origin charge where the charge at .45 would be F=kq/.45^2 and in relation with charge 4q F-k4q/X^2. Then since q1=q2 the formula was kq/.45^2 = k4q/x^2. simplified that into x^2=4/.45^2. Then took the square root of the answer. it was like 4.444 totally wrong. I cannot figure out this problem at all please some guidance!

• physics -

To double the force at the origin, the +4q charge must have the same effect upon the charge as the +q charge at x=0.45 m

Making the distance x = 0.9 (twice that of the second charge) will result in the same force produced by the +4q particle, because of the the inverse square law.

You were OK with this equation
q/(0.45)^2 = 4q/(0.9)^2

Your mistake was algebra in the next step.
k*q/.45^2 = k*4q/x^2.
x^2 = 4*(0.45)^2
x = 0.9

## Similar Questions

1. ### Physics

1.There are four charges, each with a magnitude of 2.5 µC. Two are positive and two are negative. The charges are fixed to the corners of a 0.29 m square, one to a corner, in such a way that the net force on any charge is directed …
2. ### physics

Three charges are arranged as follows: +3 mC located on the y-axis at +15 mm; -2.5 mC located on the x-axis at -25 mm; and +4.0 mC located at the origin. Determine the magnitude of the force acting on the charge located at the origin.
3. ### Physic

A point charge q1=-8 is located at the orgin of a rectangular coordinate system. A second charge q2=6nC is located at a distance of 0.2m from the orgin on the positive x-axis, and a third charge q3=12nC is located at a distance of …
4. ### physic

two point charges are located on the y axis as follows : charge q1 = -1.50nc at y= -0.600m, and charge q2 = +3.2nc at the origin (y=0) what is the net force (magnitude and direction) exerted by these two charges on a third charge q3 …
5. ### Physics

A 2.2 uC charge is located on the x-axis at x = -1.5 m. A 5.4 uC charge is located on the x-axis at x = 2.0m. A 3.5 uC charge is at the origin. Find the net force acting on the 3.5 C charge.
6. ### Physics

A 2.2 C charge is located on the x-axis at x = -1.5 m. A 5.4 C charge is located on the x-axis at x = 2.0m. A 3.5 C charge is at the origin. Find the net force acting on the 3.5 C charge.
7. ### Physics

A 2.2 C charge is located on the x-axis at x = -1.5 m. A 5.4 C charge is located on the x-axis at x = 2.0m. A 3.5 C charge is at the origin. Find the net force acting on the 3.5 C charge.
8. ### science

three point charges are located on the positive y-axis of a coordinate system.charge q1 = -2.09 nC is 2.05 m from the origin and charge q2 = +2.70 nC is 3.25 m from the origin, and the third charge q3 = -2.56 nC is located 5.03 m on …
9. ### Physics

A positive charge magnitude q1=35.5 nc is located at origin. A negative charge q2= -4.5 nc is located on positive x axis at p= 16cm from origin. Calculate the location on the x axis in cm where electric field is zero. So far I know …
10. ### Phys1402

Object A of charge 5e-6 C is located at the origin of a coordinate plane. Object B of charge 3e-6 C is located on the x-axis of a coordinate plane at x = 0.002 m. Object C of charge 3e-6 C is located on the y-axis of a coordinate plane …

More Similar Questions